The code is a one-time use code that is good for up to four tickets. You would also have to purchase tickets to one of the sessions of the GLI. If you had signed up through the Red Wings or Maple Leafs for ticket updates, then they should have sent you an e-mail with your account number & purchase window. You don't have to be an STH in order to get this, I believe they had their purchase opportunity earlier.
The nice thing about the tickets this time is that they opened pretty much all of the sections at Michigan Stadium for purchase. Last year, people that had these codes could only get seats in the end-zones, nothing along the sides, or up in the club seats.